Some small last-minute adjustments marked the absence of the Duke of Edinburgh from the Queen's side during the final day of the diamond jubilee celebrations.

At a service of thanksgiving at St Paul's Cathedral, the monarch cut a rather solitary figure as she processed alone behind the lord mayor of London who, in accordance with tradition, carried the pearl sword symbolic of the sovereign's authority.

The red velvet cushioned seat, which Prince Philip has sat in for so many services during his wife's long reign, was occupied instead by the Prince of Wales. His seat in the royal car, which bore the Queen to the morning service, was taken by her lady-in-waiting, Diana Marion, the Lady Farnham.

The only reference in the cathedral to his sudden indisposition, as he underwent treatment for a bladder infection at King Edward VII hospital in central London, was a hasty addendum to the sermon delivered by the archbishop of Canterbury, Rowan Williams.

To the congregation, which included the prime minister, David Cameron, Williams praised the Queen's dedication. "She has made her public happy and all the signs are that she is herself happy, fulfilled and at home at these encounters," he said.

"The same, of course, can manifestly be said of Prince Philip, and our prayers and thoughts are very much with him this morning."

The duke was admitted to hospital just hours ahead of the BBC jubilee concert on Monday night, and the day after taking part in the river pageant.

After the enthusiasm of last night's musical extravaganza, Tuesday's celebrations were to be of a more traditional and solemn nature: with aGuildhall reception and a lunch at Westminster Hall followed by a carriage procession of the most senior royals back to Buckingham Palace. The Queen was to have travelled in the 1902 state landau with Prince Philip, but palace officials quickly reorganised, and announced on Tuesday morning that she would be accompanied by Prince Charles and the Duchess of Cornwall.